The invention relates to methods and apparatus for displaying stored radiographs, particularly intra-oral radiographs.
It is well known in the field of oral radiology to mount dental radiographs in a film holder. Use of such film holders minimizes the possibility of misinterpretation of radiographs which, when loose and unmounted, can appear to be quite similar to one another. Such film holders can hold as few as one dental radiograph, or as many as 20 or more radiographs. Interpretation of such mounted radiographs is facilitated by mounting each film in normal anatomic relation to each other. In other words, each mounting position in a dental film holder corresponds to a particular anatomical site or anatomical region. Such mounting of dental radiographs also facilitates repeated study and comparison of sets of radiographs taken at different times in order, for example, to assess the progress of a particular dental treatment.
In addition, the mounting of dental radiographs in film holders in normal anatomic relation allows a dentist, having knowledge of normal radiologic anatomy and knowledge of anatomical landmarks, to quickly and easily interpret any set of mounted dental radiographs. The anatomical landmarks used by dentists include: the maxillary molar area (including the posterior wall of the maxillary tuberosity, the hamular process, the coronoid process of the mandible, the maxillary sinus, and the zygomatic process); the maxillary premolar area (including the maxillary sinus); the maxillary incisor area (including the incisive foramen, the cartilage of the nose, the nasal septum, and the nasal fossae); the mandibular molar area (including the external oblique line, the mylohyoid ridge and the mandibular canal); the mandibular premolar area (including the mylohyoid ridge and the mental foramen); and the mandibular incisor area (including the mental ridges, lingual foramen and the genial tubercles). Film holders present films taken of these anatomical landmark sites in positions that are consistent from holder to holder.
Recent advances in dental radiology include the use of x-ray sensitive sensors in place of film to produce digitized x-ray images which are stored in a computer memory and viewed on a computer monitor. In one such computer system, intra-oral x-ray images are created and stored along with information regarding patient identification and the number of the tooth in the image. Sets of images (constituting, for example, a dental survey), can be stored and recalled for display. When sets of related images are displayed, miniature versions of the images are presented in one portion of the display monitor for selection by the user, and are displayed in another portion of the monitor.
However, these miniature representations of the images are in no particular order, requiring the user carefully to assess which image among the set of images is the image desired to be displayed and studied. This system becomes particularly awkward as the number of images in a set increases given the fact intra-oral radiographs of different anatomical sites can appear to be quite similar.